1 /*

     2 * Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:

    15 *

    16 */

    17 

    18 

    19 #ifndef HGSCROLLBUFFERMANAGER_H_

    20 #define HGSCROLLBUFFERMANAGER_H_

    21 

    22 #include <qobject>

    23 #include <QTimer>

    24 

    25 class HgScrollBufferManager: public QObject

    26     {

    27     Q_OBJECT

    28 public:

    29 

    30     HgScrollBufferManager(

    31             int bufferSize,

    32             int bufferTreshold,

    33             int initialPosition,

    34             int totalCount);

    35 

    36     virtual ~HgScrollBufferManager();

    37 

    38     void resetBuffer(int aPosition, int aTotalCount);

    39 

    40     void scrollPositionChanged(int newPosition);

    41 

    42     bool positionInsideBuffer(int position);

    43 

    44     void removeItems(int start, int end, int totalCount);

    45     void addItems(int start, int end, int totalCount);

    46     void moveItems(int start, int end, int target, int totalCount);

    47 

    48     void currentBuffer(int& bufferStart, int& bufferEnd);

    49 

    50 signals:

    51 

    52     void releaseItems(int releaseStart, int releaseEnd);

    53     void requestItems(int requestStart, int requestEnd);

    54 

    55 protected slots:

    56 

    57     void timeout();

    58 

    59 protected:

    60 

    61     void init();

    62     void asyncUpdate();

    63     bool isInsideBuffer(int pos);

    64     bool isInsideBuffer(int start, int end);

    65 

    66 private:

    67 

    68     int mBufferSize;

    69     int mBufferTreshold;

    70     int mBufferPosition;

    71     int mDiff;

    72     int mTotalCount;

    73 

    74     bool mResetOrdered;

    75 

    76     int mRequestStart;

    77     int mRequestCount;

    78     int mReleaseStart;

    79     int mReleaseCount;

    80     QTimer mTimer;

    81 

    82 private:

    83     Q_DISABLE_COPY(HgScrollBufferManager)

    84     };

    85 

    86 #endif /*HGSCROLLBUFFERMANAGER_H_*/